package log

import (
    "bytes"
    "fmt"
    "log"
    "sort"
)

// field used for sorting.
type field struct {
    Name  string
    Value interface{}
}

// by sorts fields by name.
type byName []field

func (a byName) Len() int           { return len(a) }
func (a byName) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
func (a byName) Less(i, j int) bool { return a[i].Name < a[j].Name }

// handleStdLog outpouts to the stlib log.
func handleStdLog(e *Entry) error {
    level := levelNames[e.Level]

    var fields []field

    for k, v := range e.Fields {
        fields = append(fields, field{k, v})
    }

    sort.Sort(byName(fields))

    var b bytes.Buffer
    fmt.Fprintf(&b, "%5s %-25s", level, e.Message)

    for _, f := range fields {
        fmt.Fprintf(&b, " %s=%v", f.Name, f.Value)
    }

    log.Println(b.String())

    return nil
}
